Acquired human immunodeficiency syndrome (hereinafter sometime called merely as "AIDS") has been found to be a disease which is caused due to human T-cells being infected by a causative virus in human blood. The virus which is causative of the acquired human immunodeficiency syndrome is usually termed as acquired human immunodeficiency syndrome virus which is often abbreviated as HIV. It has been reported that certain known compounds are useful as an agent for inactivating HIV or an antiviral agent against HIV. However, any of these compounds is not necessarily satisfactory as a useful remedial agent for AIDS.
AIDS is an important disease which brings about serious problems in human society, and there is a strong outstanding demand to develope and provide such a new drug which can show a high activity to inhibit infection with HIV and which are expectable as a useful medicinal agent for therapeutically or preventively treating patients with AIDS.
On the other hand, we, the present inventors, and our associates have discovered that when a strain of Actinomycetes, designated as MH193-16F4 strain, is cultured in a culture medium under aerobic conditions, two antibiotics named as benanomicin A and benanomicin B are produced and accumulated in the culture. Benanomicin A and benanomicin B as well as salts thereof have been found to have strong antifungal activities in vivo, and benanomicins A and B have been found to be represented by a general formula (I): ##STR1## wherein R denotes a hydroxyl,group for benanomicin A and R denotes an amino group for benanomicin B,
Benanomicin A and benanomicin B as well as salts thereof are described in the "Journal of Antibiotics" Vol. 41, page 807 (June, 1988) and in the specification of our co-pending Japanese patent application No. 277,692/87 filed Nov. 2, 1987 (now laid-open under Japanese patent appln. first publication "Kokai" No. 121293/89 on 12 May 1989) and in the specification of the corresponding U.S. patent application Ser. No. 264,888 (filed Oct. 31, 1988) now U.S. Pat. No. 5,055,453 or the corresponding European patent application No. 88-118,253.9 filed Nov. 2, 1988 (now laid-open under European patent appln. publication No. 0 315 147 A2 on May 10, 1989).
Benanomicin A is an acidic substance in the form of a reddish brown powder which has a melting point higher than 220.degree. C. and is only sparingly soluble in methanol, chloroform, ethyl acetate and acetone but is soluble in dimethylsulfoxide, dimethylformamide and alkaline water and insoluble in water. Benanomicin B is an amphoteric substance and benanomicin B hydrochloride is in the form of a reddish brown powder which has a melting point higher than 220.degree. C. and a specific rotation [.alpha.].sup.22 .sub.D +360.degree. (c 0.05, water) and is only sparingly soluble in chloroform, ethyl acetate and acetone and is soluble in methanol, dimethylsulfoxide, dimethylformamide and water.